Most wristop devices equipped with a heart rate monitor guide exercise in a selected manner. The user selects an operating mode, which can be, for example, the achievement of a selected training effect, an increase in endurance, or a reduction in weight. User-specific parameters, which are, for example, sex, age, weight, and height, are entered in the device when it is begun to be used. It is easy for the user to set these data in the device. However, it is difficult for the user to provide, for example, information on the maximum heart rate level (HRmax) and the fitness level (VO2max), as well as the activity class. As such, it is already known that a device (for example, a heart rate monitor) can propose, for example, increasing the HRmax value, if a heart rate value higher than the default value or set value appears in use.
Nowadays, web-based services are also popular, in which the data of the heart rate monitor are transmitted through the internet to a server, with the aid of which a computer program, performing physiological computation, is used. Publication US 2007/0082789 A 1 discloses a method for determining a person's performance from physical exercise. The method cannot, however, be utilized during exercise, but instead requires the data to be analysed separately after exercise.
A method is known from publication WO 2009/133248 for determining a free fitness level from exercise, in which heart rate and external output, such as, for example, speed and height together, are measured periodically. A bicycles ergometer and many other exercise devices give the external output directly and, if the speed of running exercise, for example, is measured together with altitude information, it is possible to determine what the external work output is. With the aid of free exercise, as long as there is enough data, the level of the fitness of the user's respiratory and cardiovascular system (cardiorespiratory) fitness level can be determined. However, the method requires relatively long (30 s-4 min) stable periods. The method is difficult to apply to the automatic determining of fitness level.
Publication US 2012/0029370 (WO 2010/112010 A1) discloses a method using short standard loadings to determine fitness level.